Clarify project setup steps

content/tutorial/tutorial.md

@@ -81,11 +81,22 @@ npm install -g create-react-app
 create-react-app my-app
 ```
 
-3. Delete all files in the `src/` folder of the new project (don't delete the folder, just its contents).
+3. Delete all files in the `src/` folder of the new project 
+
+> Note: **don't delete the folder, just the original source files**.  We'll replace the default source files with examples for this project in the next step.
 
 ```bash
 cd my-app
-rm -f src/*
+cd src
+
+# If you're using a Mac or Linux:
+rm -f *
+
+# Or, if you're on Windows:
+del *
+
+# Then, switch back to the project folder
+cd ..
 ```
 
 4. Add a file named `index.css` in the `src/` folder with [this CSS code](https://codepen.io/gaearon/pen/oWWQNa?editors=0100).